<?php

require_once 'HTMLPurifier/AttrDef.php';
require_once 'HTMLPurifier/AttrDef/CSS/Color.php'; // for %Core.ColorKeywords

/**
 * Validates a color according to the HTML spec.
 */
class HTMLPurifier_AttrDef_HTML_Color extends HTMLPurifier_AttrDef
{
	
	function validate($string, $config, &$context) {
		
		static $colors = null;
		if ($colors === null) $colors = $config->get('Core', 'ColorKeywords');
		
		$string = trim($string);
		
		if (empty($string)) return false;
		if (isset($colors[$string])) return $colors[$string];
		if ($string[0] === '#') $hex = substr($string, 1);
		else $hex = $string;
		
		$length = strlen($hex);
		if ($length !== 3 && $length !== 6) return false;
		if (!ctype_xdigit($hex)) return false;
		if ($length === 3) $hex = $hex[0].$hex[0].$hex[1].$hex[1].$hex[2].$hex[2];
		
		return "#$hex";
		
	}
	
}

